Diagnostic system for sensing and displaying functions of a motor vehicle heating apparatus

ABSTRACT

A diagnostic system for sensing and displaying malfunctions of a heating apparatus installed in a vehicle, wherein the display is effected by a display device of an on-board timer for the heating apparatus.

FIELD OF THE INVENTION

The invention relates to a diagnostic system for sensing and displayingthe manner in which functions are performed, in particular malfunctions,in a heating apparatus, especially an additional heating apparatus,installed in a vehicle, including a controller for controlling thefunctions of the heating apparatus, a monitoring means for monitoringthe correctness of the functions and for issuing malfunction signals incase of improper functions, a diagnosis memory for storing at least theoccurrence of malfunction signals, and a display device for displayingmalfunction signals stored in said diagnosis memory.

BACKGROUND OF THE INVENTION

The electronic system controlling the functions of the heating apparatusis also responsive to malfunctions. The heating apparatus is usually putout of operation then. To this end, there is provided a monitoring meansmonitoring the functions of the heating apparatus with respect to thecorrectness thereof or with respect to the occurrence of malfunctions.Malfunction signals indicating the occurrence of malfunctions areusually stored in a diagnosis memory, in the form of error codes. Incase the diagnosis memory is composed with an EEPROM, the error codesare permanently stored in the diagnosis memory. For motor vehicles ofmore recent construction dates, there are diagnostic systems which areused by motor vehicle garages for finding malfunctions of the motorvehicle, in particular of the engine and the electronic system of theengine. The motor vehicle electronic system is provided with adiagnostic connector through which a diagnostic apparatus may beconnected. The diagnostic apparatus comprises a display device by meansof which malfunctions of the motor vehicle can be displayed. Additionalheating apparatus for motor vehicles are thus usually equipped withcontrollers permitting communication of the diagnosis memory of theheating apparatus with the diagnostic apparatus used for inspection ofthe motor vehicle.

Different motor vehicle manufacturers employ different data transfermethods for reading out information, in particular malfunctioninformation, through the respective diagnostic apparatus connectablethereto. The diagnostic apparatus usable in each particular case must bematched to the data protocol corresponding to the respective specificdata transfer method employed. For rendering the diagnostic informationof the heating apparatus displayable via the diagnostic apparatus usedfor a particular motor vehicle, the controller of the heating apparatusmust be matched individually to the data transfer method used for aparticular vehicle type, or it must be matchable thereto by selection.In order to avoid that a plurality of different heating apparatus withcorresponding individually matched controllers have to be provided, butto allow instead the use of just one single type of heating apparatus,the controller of the heating apparatus has to be provided with amultiplicity of data transfer methods along with the associated dataprotocols which may be retrieved selectively in order to permitcooperation of the diagnostic system of the heating apparatus with thediagnostic apparatus usable for a specific motor vehicle type. Thisentails a considerable circuit expenditure in the controller of theheating apparatus, along with a correspondingly high expenditure ofcomponents and costs.

A possibility of getting away from this problem consists in providing inthe motor vehicle a display lamp which, in accordance with theparticular malfunction to be displayed, indicates an error code by wayof a specific blinking sequence. The user must be capable ofinterpreting and evaluating the error code indicated by the blinkingsequence. This may easily result in interpretation errors, even when theblinking code is employed in a garage authorized to repair the heatingapparatus. This risk is particularly high when a larger number ofmalfunctions can be diagnosed and displayed. For reducing the frequencyof misinterpretations in this respect, it is possible to greatlyrestrict the number of the displayable blinking codes and thus thenumber of the displayable malfunctions, so that only selected errors arestill indicated, for example overheating of the heating apparatus. Thisentails the serious drawback that the additional, not displayablemalfunctions are no longer recognizable via the diagnostic display andtreatable. For example, it may also be of interest to detect by means ofthe diagnostic system not only malfunctions that have already occurred,but also to obtain trend displays by means of which the trend towards amalfunction can be diagnosed at an early stage.

SUMMARY AND OBJECTS OF THE PRESENT INVENTION

It is the object of the invention to make available a diagnostic systemof the type indicated at the outset, which permits the display also of alarge number of possible malfunctions and, if desired, also of errortendencies in an easily readable manner, with as little circuitexpenditure and costs as possible and independently of the individualmotor vehicle types.

According to the invention, a diagnostic system is provided for sensingand displaying the manner in which functions are performed, inparticular for sensing and displaying malfunctions, of a heatingapparatus installed in a vehicle. The system includes a controller forcontrolling the functions of the heating apparatus. A monitoring deviceis provided for monitoring the correctness of the functions and forissuing malfunction signals in case of functions not performed properly.A diagnosis memory is provided for storing at least the occurrence ofmalfunction signals. A display device is provided serving for displayingmalfunction signals stored in the diagnosis memory, the display deviceincludes a display device of a timer provided in the vehicle for timingthe heating apparatus and having a switching time input device. Thetimer includes an error code decoder decoding error codes, which areread out from the diagnosis memory in accordance with various detectablemalfunctions, into display signals that are fed to the display device ofthe timer and effect an error display there. The switching time inputdevice is provided for inputting the functions of the heating apparatusto be controlled by the timer and the switching time at which thisfunction is to be carried out. The timer has a timing signal decoder bymeans of which the function input and the switching time input aredecoded into display signals for the display device. The timing signaldecoder and the error code decoder are constituted by one single commondecoder.

Additional heating apparatus for motor vehicles, but also for cranes,excavators etc., nowadays are as a rule provided with a timer, throughthe control of which the heating apparatus is turned on and/or off at apreset time. This allows, for example, preheating of a motor vehicleduring a presettable period of time before the motor vehicle is beingused. Such a timer has a display device on which the desired switchingon and/or switching off time can be displayed for the purpose of settingthe switching times and for the purpose of checking the set switchingtimes. The invention is based on the idea of providing the heatingapparatus with an independent diagnostic system, i.e. an on-boarddiagnostic system that is not dependent on diagnostic apparatus used fordiagnosing the individual motor vehicle types, in that the displaydevice of the on-board timer is employed for the heating apparatus.

The same display elements of the display device of the timer may be usedfor displaying the timing signals and the error codes. The commondecoder may perform, in reversible manner, either timing signal decodingor error code decoding and may deliver to the display elements of thedisplay device display signals corresponding either to the timingsignals or to the error codes, depending on the particular switchingstate.

The display device of the timer, in addition to the indications relatedto the heating apparatus, may be adapted to display further indications,for example the time, the outside temperature measured by an externalthermometer of the vehicle, and the like.

The timer may comprise a diagnosis request device which, inpredetermined time intervals and/or in case of manual operation by theuser of the vehicle or a maintenance or repair service for the heatingapparatus, effects taking over of stored error codes in the error codedecoder and thus results in a display of malfunctions of the heatingapparatus that possibly have occurred.

Error codes stored in the diagnosis memory may be continuouslytransferred to the common decoder. The common decoder may have anautomatic selection means associated therewith which controls the commondecoder so as to issue either display signals resulting in indication oferror codes on the display device, or to issue display signals resultingin display of other information, such as the timing indication andpossibly the time, outside temperature etc.

The selection means may include a priority means which, upon transfer ofan error code from the diagnosis memory, controls the common decoder soas to issue display signals for displaying the error code.

The timer may be provided with a resetting means through which thediagnosis memory can be reset by the timer upon elimination of the causefor displaying error codes.

The monitoring device comprises a tendency detecting means through whichfunctions of the heating apparatus can be detected which are not yetrated as malfunctions but indicate a tendency towards the occurrence ofmalfunctions. Such tendency signals delivered by the tendency detectingmeans can be stored in the diagnosis memory in the form of tendencycodes. The tendency codes can be transferred to the error code detectorof the timer. The timer may be provided with a selecting means operableby the user of the vehicle or starting operation automatically, by meansof which received tendency codes can be suppressed or indicated asregards indication thereof by the display device of the timer.

The invention will now be elucidated in more detail by way of anembodiment shown in the sole accompanying drawing FIGURE.

The various features of novelty which characterize the invention arepointed out with particularity in the claims annexed to and forming apart of this disclosure. For a better understanding of the invention,its operating advantages and specific objects attained by its uses,reference is made to the accompanying drawings and descriptive matter inwhich a preferred embodiment of the invention are illustrated.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

The only FIGURE is a block circuit diagram

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawing in particular, the drawing shows schematicallya block circuit diagram, a heating apparatus 11 and a timer 13. Theheating apparatus 11 preferably is an additional heating apparatus of amotor vehicle, which may be used as an auxiliary heating apparatus forheating while the engine is not running, or an additional heatingapparatus while the engine is running and the vehicle heating system fedby the engine cooling system is in operation.

The heating apparatus 11 and the timer 13, in the embodiment shown, arefed from the same energy source, namely a current supply source having apositive terminal and a negative terminal. The distribution of thecurrent supply to the individual components of heating apparatus 11 andtimer 13 is not shown.

The heating apparatus comprises, in the usual and known manner, aplurality of components, such as a combustion engine 15, a heater plug17 for igniting the heating apparatus fuel, a flame detector 19 and aregulating detector 21. Additional components may be provided, asindicated by the four dots below the aforementioned components 15 to 21.

The heating apparatus 11 comprises a controller 23 for controlling thefunctions of the individual components 15 to 21 of the heating apparatus11. The controller 23 to this end comprises a control means 25.Especially for reasons of safety, the functions of the individualcomponents 15 to 21 of the heating apparatus 11 are continuouslymonitored with the aid of a monitoring device 27. The monitoring device27 is suitable on the one hand for detecting serious malfunctionsresulting in safety switching-off of the heating apparatus 11, on theother hand, it is also possible to detect less serious malfunctions orfunctional trends announcing a possible or imminent malfunction.

When the heating apparatus has been put out of operation, i.e. switchedoff, by the monitoring device due to a serious malfunction, eliminationof the cause of the malfunction with as little expenditure as possibleis to be rendered possible in that an indication is provided as to whatmalfunction caused standstill of the heating apparatus 11. But also incase of less serious malfunctions, for example malfunctions which,though not cogently resulting in switching off of the heating apparatus11, do no longer permit optimum operation thereof, it is advantageous toobtain an indication of the existing malfunction during maintenance orrepair of the heating apparatus 11. Indication of a malfunction isparticularly valuable when a malfunction does not occur permanently butonly from time to time, and not at the time during maintenance or repairof the heating apparatus 11.

For being able to find out under all these circumstances whichmalfunction is present at the moment or has occurred therebefore,malfunctions detected by the monitoring device 27 are stored in adiagnosis memory. This is preferably an EEPROM memory, i.e. aprogrammable non-volatile read-only memory whose memory contents can beerased electronically. The various malfunctions are stored in thediagnosis memory 29 in the form of different error codes. These can beread out from the diagnosis memory at the desired moments of time withthe aid of a memory read-out control 31.

The timer 13 comprises in usual manner a display device 33 havingdisplay elements (not shown in detail in the FIGURE) whose operation iscontrolled by a decoder 35. The latter delivers to the display device 33display signals resulting in display of specific information. Timer 13comprises furthermore a timing circuit 37 which may be preset by theuser of the motor vehicle provided with the heating apparatus 11 todesired switching-on times and/or switching-off times by means of aswitching time input device 39. Timing control 37 comprises a clock notshown in the FIGURE itself. When the switching times preset by means ofthe switching time input device 39 have been reached, the timing circuit37 delivers corresponding control signals to the control means 25 of theheating apparatus 11, which then controls the individual components 15to 21 of the heating apparatus 11 in corresponding manner.

Timing circuit 37 supplies to decoder 35 a signal that may be decoded bydecoder 35 and displayed on display device 33. In this manner, thefollowing information, for example, may be displayed on display device33:the current time, the switching-on time and the switching-off time ofthe heating apparatus 11. In addition thereto, the display device 33 maybe utilized during selection of the switching-on time and/or theswitching-off time by actuation of the switching time input device 39.

Decoder 35 furthermore is connected to memory readout control 31 throughwhich decoder 35 may be fed with the error codes stored in diagnosismemory 29. After decoding thereof in decoder 35, the stored error codesmay then be displayed by display device 33.

Timer 13 comprises furthermore a diagnosis request device 41 that isconnected to decoder 35 and furthermore may be connected to the memoryread-out control 31 (for this reason, the latter connection is shown inbroken lines). With the aid of the diagnosis request device 41, anoperator, either the user of the motor vehicle or a maintenancetechnician, can obtain an indication of malfunctions stored in diagnosismemory 39 on display device 33. In this respect, it is possible by acorresponding input via the diagnosis request device 41 to obtain adisplay only of one malfunction or of a choice of stored malfunctions,or all malfunctions stored may be indicated at the same time when thedisplay device 33 has a corresponding display capacity.

It is possible to provide for the timing control and for the errordiagnosis display a separate decoder each or, as in case of theembodiment shown in the FIGURE, a common decoder for the timing functionand the diagnosis display function.

When the display device 33 has a sufficiently great display capacity,one or more malfunctions stored in diagnosis memory 29 may be indicatedin addition to a continuously displayed signal, for example the currenttime. However, the diagnostic system may also be designed such thattimer 13 is provided with an automatic selection means through which, incase time signals and malfunction signals are present at the same time,an automatic selection (preferably in preselectable manner) is made suchthat only one of these two signal types is displayed. For example, thedecoder 35 may have a priority means (not shown) associated therewith bymeans of which a display priority is allocated to malfunction signalscoming from the memory read-out control 31 in such a manner that uponoccurrence of a malfunction and storage thereof in diagnosis memory 29,the display indicated so far, for example the time indication, isinterrupted and the malfunction is displayed in order to inform the userof the motor vehicle thereof immediately as of the occurrence of themalfunction.

It is also possible to design the diagnostic system such that the errorcodes, provided that such codes are stored in diagnosis memory 29, aretransmitted by timer 13 only upon request. This can take placeautomatically, for example, after predetermined time intervals or timeintervals that are adjustable via the diagnosis request device 41. Ifhowever the "freerunning telegram" method is employed, in which theerror codes stored in diagnosis memory 29 are permanently transferred todecoder 35 via memory read-out control 31, the decoder 35 controls atwhat time and whether the detected malfunctions are displayed, forexample in accordance with the aforementioned priority routine.

Timer 13 in preferred manner is provided with a resetting means (notshown) by means of which diagnosis memory 29 can be reset or erased bymeans of timer 13 after the cause of the malfunction stored in diagnosismemory 29 has been eliminated.

Decoder 35, in the manner shown in the FIGURE, may be provided with anadditional signal input 43 through which additional signals may besupplied from the vehicle. It is thus possible, for example, to displaythe outside temperature measured by an external thermometer of the motorvehicle on display device 33, or the like.

While a specific embodiment of the invention has been shown anddescribed in detail to illustrate the application of the principles ofthe invention, it will be understood that the invention may be embodiedotherwise without departing from such principles.

I claim:
 1. A diagnostic system for sensing and displaying the manner in which functions are performed for sensing and displaying malfunctions of a heating apparatus installed in a vehicle, said system comprising:a controller for controlling the functions of the heating apparatus; a monitoring device for monitoring the correctness of the functions and for issuing malfunction signals in case of functions not performed properly; a diagnosis memory for storing at least the occurrence of malfunction signals; a timer provided in the vehicle for timing the heating apparatus, said timer having a switching time input device for input of functions of the heating apparatus to be controlled by said timer and for input of a switching time at which said functions are to be carried out, error code decoder means for decoding error codes, which are read out from said diagnosis memory in accordance with various detectable malfunctions, into display signals and timing signal decoder means for decoding a function input and a switching time input into display signals, said timing signal decoder means and said error code decoder means being provided in a single common decoder, said timer including a display device for displaying said display signals.
 2. The diagnostic system according to claim 1, wherein said display device includes display elements used for displaying timing signals and the error codes, and said common decoder performs, in reversible manner, either timing signal decoding or error code decoding and delivers to said display elements of the display device said display signals corresponding either to the timing signals or to the error codes, depending on a particular switching state.
 3. The diagnostic system according to claim 1, wherein said display device of said timer displays further indications including an outside temperature measured by an external thermometer of the vehicle.
 4. The diagnostic system according to claim 1, wherein said timer includes a diagnosis request device which effects taking over stored error codes in the error code decoder resulting in a display of malfunctions of the heating apparatus that possibly have occurred, said diagnosis request occurring at least at one of predetermined time intervals and by input command of a user.
 5. The diagnostic system according to claim 2, wherein said error codes stored in said diagnosis memory are continuously transferred to said common decoder, said common decoder having an automatic selection means associated therewith for controlling said common decoder so as to issue either display signals resulting in indication of error codes on the display device, or to issue display signals resulting in display of other information including a timing indication.
 6. The diagnostic system according to claim 5, wherein said selection means includes priority means which, upon transfer of an error code from the diagnosis memory, controls said common decoder so as to issue display signals for displaying said error code.
 7. The diagnostic system according to claims 1, wherein said timer is provided with a resetting means through which said diagnosis memory can be reset by the timer upon elimination of a cause for displaying error codes.
 8. The diagnostic system according to claim 1, wherein said monitoring device comprises a tendency detecting means through which tendency signals are generated representing functions of said heating apparatus which can be detected which are not yet rated as malfunctions but indicate a tendency towards the occurrence of malfunctions, said tendency signals being stored in said diagnosis memory as tendency codes, said tendency codes being transferable to said error code decoder means of said timer, and said timer being provided with a selecting means, said selecting means being one of operable automatically and operable by a user of the vehicle, said selecting means for suppressing received tendency codes or indicating received tendency codes via said display device. 